Two 19-year-old students from the Chicago area have been found dead in two campus dormitories at Illinois State University, but school officials say no foul play or criminal activity is suspected in either case.

Allison Zak, a sophomore from Schaumburg, was found unresponsive in Manchester Hall around 9:30 p.m. Thursday, according to the McLean County coroner's office. She was pronounced dead on the scene an hour later.

Shortly before midnight, John Cody Stephens, a freshman from Wilmette, was found unresponsive in Hewett Hall, the coroner's office said. He was pronounced dead at 12:30 a.m. today.

In both cases, the coroner's office said "no signs of life were found" when officials arrived on the scene.

Preliminary information from autopsies performed today indicated Zak's death was medically related, while Stephens died of "a non-natural process."

Zak's might be related to an undiagnosed seizure disorder or infarct related to her Crouzon Syndrome — a syndrome that manifests itself with multiple cerebral and cranial abnormalities, according to McLean County Coroner Beth Kimmerling.

Although it was reported to officials that Zak fell and hit her head earlier this week, the autopsy showed no fatal trauma as a result of this incident, Kimmerling said.

Forensic toxicology and microscopic tissue exam studies are pending.

Stephens’ autopsy showed his death was the result "of a non-natural process," Kimmerling said.

Forensic toxicology tests have been ordered, but no additional details will be released.

Kimmerling confirmed there is no sign of foul play or third-party involvement with either death.

"Other than the fact that both individuals were found by their respective roommates, these two young peoples’ deaths are apparently unrelated," Kimmerling said. "There are no signs of foul play or third-party involvement. The deaths were not of violent nature."

Zak was a 2010 graduate of Conant High School in Hoffman Estates, where she was a member of the orchestra and marching band, according to High School District 211 spokesman Tom Petersen.

She was the oldest of three sisters, and the two younger sisters attend Conant.

Kreg Moorhouse, the director of bands at Conant High School in Hoffman Estates, taught Zak for her final two years at the school. He called Zak, who played clarinet in both orchestra and marching band for all four years, “very smart and very well-rounded.”

“I was just shocked,” he said when he heard of the news in the morning. “She was very bright and one of my best players. She took a lot of pride in that. She took that marching band uniform and wore it with pride.”

He described Zak as someone who took both her music and her academics very seriously, and he couldn’t recall her ever missing class. He called her a well-natured and well-mannered student who he expected great things of in the future.

“Here’s this great girl who is involved in all this ... It’s just disbelief,” Moorhouse said. “She was focused on what she was going to achieve. She knew what she wanted to do. I saw that in her.”

Friday was the last day before spring break, but counselors will be provided for students when they return April 2, officials said.

Stephens graduated last year from New Trier Township High School, spokeswoman Nicole Dizon said.

New Trier student David Resnick said he met Stephens, who went by Cody, at a computer networking and repair class last year at the Wilnnetka high school, where Resnick said his friend was also involved in the audio-visual club.

"I'm completely in shock,” Resnick said. “Cody was a great guy. He said he had a great sense of humor, and he spent a lot of time on the Internet. He especially enjoyed Internet humor and news."

A Wilmette Park District official confirmed that Stephens had worked for the district as a lifeguard.

The two lived in high-rise dorms at the East Campus Complex that shared an underground student area with a lounge, offices, vending machines and a computer lab.

At Stephens' dorm door, two messages were scrawled in black marker near the bottom corner of his mint-green name tag.

"Love you, Cody!" one read.

"I will miss you always," said the other.

Sri Eladasar, 19, said her neighbors on the 16th floor of Hewett told her of Stephens' death when she arrived home early this morning.

"It's really shocking," said Eladasar, a freshman. "I've seen people in tears and everyone's just been really down. I just feel so bad for his roommates. Having to come back to something like that would be horrible."

The deaths were disclosed early this morning in a letter by university president Al Bowman on the school's website.

"It is with deep sadness that I must alert you to two tragic incidents that occurred on Illinois State’s campus during the evening and overnight hours," he wrote. "Two students were found deceased in their residence hall rooms.

"I want to assure you that the incidents are unrelated, and that there is no foul play or criminal activity of any kind involved in either incident," he said.

Deaths among the Bloomington-Normal school's 21,000 students are rare. In his 30 years on campus, ISU spokesman Jay Groves said, he had never known of two students dying in such a short time frame.